Functional Nanocomposite Thin Films Deposited by Plasma Deposition

• Main Authors: Kuo-ChengChen, 陳國政
• Other Authors: Franklin Chau-Nan Hong
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/50052498308210268277

博士 === 國立成功大學 === 化學工程學系碩博士班 === 100 === Diamond-like carbon (DLC) nanocomposite films containing nanostructures were synthesized by various deposition techniques, including inductively-coupled plasma chemical vapor deposition (ICP-CVD), sputtering-assisted CVD, capacitive-coupled plasma CVD, plasma jet CVD etc. By incorporating high densities of ceramic nanoparticles (SiC, Si3N4, ZrO2, TiC, TiO2, ZnO, etc.) and nano-carbons, DLC nanocomposites can present the increase of film hardness and the reduction of film stress, as well as the enhancement of toughness, increase of film adhesion, and decrease of friction coefficients with novel function of light-induced hydrophilicity. SiCxNy nanocrystallites-containing DLC nanocomposite films were prepared by ICP-CVD using a hexamethyldisilazane (HMDSN) precursor. The substrate was biased by a pulsed-DC power supply to provide the necessary energy of deposited ions. The effects of substrate bias on the surface morphology, roughness, and the mechanical properties of nanocomposite film were well investigated. The results revealed the film has maximum hardness of 15 GPa at a relative low stress of 0.5 GPa at an ICP power of 100W, and a substrate bias of -200V. The films exhibited a lower coefficient of friction in the range of 0.06 to 0.09 via nano-scratch technique, and had lower wear depth with a good wear performance using nano-wear test. The fracture toughness of the film was greatly enhanced by the incorporation of SiCxNy nanoparticles in the DLC matrix, measured from its resistance to crack propagation by the indentation method of Vickers indenter. Zirconia-containing DLC nanocomposite films were prepared by sputtering-assisted plasma CVD. ZrO2-DLC films were deposited using acetylene as the carbon source, and argon was used to sputter ZrO2 target. AFM results show that the surface of the films is very smooth. The tribological properties of the films could be controlled by adjusting the substrate biases during depositions. A higher energy of ion bombardment in this system biasing by pulsed-DC, induces the formation of sp2 carbon bonding in the film and makes the films’ hardness and Young’s modulus drop. The fractured toughness of DLC nanocomposite films measured by Vickers indenter were in the range from 14 to 22 MPa•m1/2, revealing the enhancement of film toughness. Nano-carbons embedded in DLC nanocomposite films were synthesized by plasma jet CVD in the mixed gases of benzene and nitrogen. Transmission electron microscopy images of the films indicate the existence of nanostructured carbon. A high degree of dissociation and reaction in plasma jet reactor and appropriate nitrogen contents in the gas phase are important for the growth of nanostructured carbon embedded in the DLC matrix. Synthesis of TiO2-DLC nanocomposite films with novel functions were studied by sputtering-assisted plasma CVD. With titanium-oxygen species sputtered from titania (TiO2) target by argon using a radio-frequency (RF) power, DLC films were simultaneously grown on the negatively-biased substrate by plasma CVD of acetylene gas using a pulsed direct-current (DC) power. By adjusting the sputtering power, both TiO2 and TiC nanoparticles could be incorporated in the DLC films. The TiO2-DLC nanocomposite films deposited at 80.7 % Ar exhibited a high hardness of around 14 GPa at a relatively low stress and, particularly, a fast rate of turning super-hydrophilic by reaching zero degree of water contact angle under 40 minutes of ultraviolet irradiation. Synthesis of amorphous boron nitride films (a-BN) at low temperature were studied by hollow cathode discharge CVD. Borazine and N2 gases were employed as the precursors to deposit a-BN films. The as-deposited films were amorphous phase with a transparent and smooth surface. Fourier transform infrared spectroscopy (FTIR) revealed that with a high nitrogen concentration and a high hollow cathode power, high content of sp3-bonded BN can be obtained. Hollow cathode plasma was essential in forming the sp3-bonded BN in the film.